The objectives of this proposal are to delineate in precise detail the effects of progesterone on hypothalamic LHRH activity and to unravel the underlying influence of monoaminergic neurons. Various nuclei containing LHRH and monoamines in the diencephalon will be microodissected. LHRH will be extracted by radioimmunoassays and the activity of the monoamines will be assessed by analyzing turnover rates using radioenzymatic procedures.